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Subject[PATCH 13/13] clocksource/drivers/dw_apb: Add reset control
Date
From: Dinh Nguyen <dinguyen@kernel.org>

Add code to retrieve the reset property from the dw-apb timers and if
the property is available, the safe operation is to assert the timer
into reset, and followed by a deassert of the timer reset (brings the
timer out of reset).

This patch is needed for systems where the bootloader has left the timer
not used in reset.

- Trivial conflict with commit a74bd1ad7a:
"Convert to using %pOFn instead of device_node.name"

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/clocksource/dw_apb_timer_of.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index fabaa29..db410ac 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -22,6 +22,7 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clk.h>
+#include <linux/reset.h>
#include <linux/sched_clock.h>

static void __init timer_get_base_and_rate(struct device_node *np,
@@ -29,6 +30,7 @@ static void __init timer_get_base_and_rate(struct device_node *np,
{
struct clk *timer_clk;
struct clk *pclk;
+ struct reset_control *rstc;

*base = of_iomap(np, 0);

@@ -36,6 +38,16 @@ static void __init timer_get_base_and_rate(struct device_node *np,
panic("Unable to map regs for %pOFn", np);

/*
+ * Reset the timer if the reset control is available, wiping
+ * out the state the firmware may have left it
+ */
+ rstc = of_reset_control_get(np, NULL);
+ if (!IS_ERR(rstc)) {
+ reset_control_assert(rstc);
+ reset_control_deassert(rstc);
+ }
+
+ /*
* Not all implementations use a periphal clock, so don't panic
* if it's not present
*/
--
2.7.4
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